The present disclosure generally relates to seismic data acquisition and processing, and more particularly to dynamic gain adjustments in seismic surveys.
Petrochemical products such as oil and gas are ubiquitous in society and can be found in everything from gasoline to children's toys. Because of this, the demand for oil and gas remains high. In order to meet this high demand, it is important to locate oil and gas reserves in the Earth. Scientists and engineers conduct “surveys” utilizing, among other things, seismic and other wave exploration techniques to find oil and gas reservoirs within the Earth. These seismic exploration techniques often include emitting seismic energy into the Earth with a seismic energy source (e.g., dynamite, air guns, vibrators, etc.), and monitoring the Earth's response to the seismic source with one or more receivers in order to create an image of the subsurface of the Earth.
Certain types of marine seismic surveys involve placing a receiver on a seafloor or towing one or more streamer cables with a plurality of receivers behind an acquisition vessel along pre-plotted sail lines. Each receiver includes, for example, a pressure sensor, a particle motion sensor, or both a pressure sensor and a particle motion sensor in proximity to one another. The pressure sensor may be, for example, a hydrophone that records scalar pressure measurements of a seismic wavefield. The particle motion sensor may be, for example, a three-component geophone or accelerometer that records vectorial velocity measurements of the seismic wavefield. By observing the reflected seismic wavefield detected by the receivers during the survey, the geophysical data pertaining to reflected signals may be acquired and these signals may be used to form an image of the Earth near the survey location. Also, similar seismic surveys can be performed on land, although a pressure sensor is typically omitted for land-based seismic surveys.
During the course of a marine seismic survey, the gain of the seismic receivers is conventionally set relatively high in order to adequately sample the relatively weak amplitude of the reflected seismic wavefields (as compared with the directly propagating seismic wavefield). As such, the seismic receivers may be overdriven by the arrival of the directly propagating seismic wavefield.